Doctoral theses
Current Record: 2408 of 2444
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| Identifier |
uch.med.phd//1995avramopoulos |
| Title |
Μελέτη του χρωμοσώματος 21. Συμβολή στη δημιουργία μειωτικού χάρτη και στη μελέτη της τρισωμίας 21 |
| Alternative Title |
Studies on chromosome 21. Contribution to the genetic map and to the study of trisomy 21 |
| Creator |
Avramopoulos, Dimitris G
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| Abstract |
The present work is a study of chromosome 21 at the molecular level. We are focusing in two fields, the construction of a high resolution linkage map using markers that can be typed with the polymerase chain reaction (PCR) and the study of the origins and mechanisms of full and mosaic trisomy 21 using polymorphic markers. Linkage maps are a very useful tool for the study of the genome, especially for the localization of genes that cause genetic diseases or predispositions. They are constructed using polymorphisms, that today are mostly at the DNA level. We searched for polymorphisms in genes that are located on human chromosome 21. We identified 7 polymorphisms in 17 genes studied and put those on the linkage map of the chromosome after genotyping the families of the Centre d'Etude du Polymorphisme Humain (CEPH). We also genotyped and put on the linkage map two highly polymorphic short sequence repeats (SSRs). Our data combined with data from other researchers were used for the construction of a linkage map of chromosome 21 that includes 43 markers typeable by PCR. We also used the above and other polymorphic markers in order to find the origin of the supernumerary chromosome in individuals with trisomy 21. This study provided additional data on the origin of non disjunction in parental meiotic errors, and also showed the existence of mitotic errors leading to trisomy 21 in 4.6% of cases. This was done by showing reduction to homozygosity for all markers studied, which where densely located along the entire long arm of chromosome 21. Polymorphic markers were also used for determining the origins of mosaicism for trisomy 21. In our sample of 18 families we found that in 59% of cases there was meiotic non-disjunction in the parents followed by mitotic chromosome loss in the embryo while in the remaining 41% the mosaicism was due to formation of a trisomic cell line due to mitotic nondisjunction in the originally euploid embryo. Our results are in accordance with speculations expressed in the past based on maternal age differences, while we found no similar study in the literature.
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| Issue date |
1995-07-01 |
| Date available |
1997-06-6 |
| Collection
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School/Department--School of Medicine--Department of Medicine--Doctoral theses
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Type of Work--Doctoral theses
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| Permanent Link |
https://elocus.lib.uoc.gr//dlib/f/d/5/metadata-dlib-1995avramopoulos.tkl
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| Views |
532 |
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